A video decoder for decoding compressed high-definition video data. The video decoder includes compress and decompress circuits placed in the decoder's datapath to reduce the amount of video data that needs to be stored in frame buffer memory. Reference frame video data is compressed by the compress circuit for storage in frame buffer memory. A rate control circuit is provided to control the rate at which the compress circuit stores reference frame video data in the frame buffer memory. The decompress circuit reconstructs the reference frames on-the-fly for use in motion compensated prediction. Methods of decoding compressed high-definition video signals are also disclosed.
Legal claims defining the scope of protection, as filed with the USPTO.
1. Apparatus for decoding a stream of compressed video data, wherein the stream includes a plurality of variable length encoded data representing image areas of transmitted frames, comprising: a decoder for decoding a block of the variable length encoded data to generate a corresponding block of decompressed data for reconstruction of the transmitted frames; memory coupled to said decoder; a compressor coupled to said decoder and said memory for variable length encoding the block of decompressed data generated by said decoder for direct storage in said memory as variable length encoded data; a rate control circuit coupled to said compressor for controlling a rate at which said compressor stores said variable length encoded data in said memory, wherein said rate control circuit is operable to allocate a fixed number of bits for the block of variable length encoded data, monitor the number of bits generated by the compressor during the encoding of the block of decompressed data, and terminate the encoding of the block of decompressed data so that the allocated fixed number of bits for the block of variable length encoded data is not exceeded; and a decompressor coupled to said memory and said decoder for decoding selected variable length encoded data stored in said memory to generate corresponding decompressed data, whereby said decoder is operable to reconstruct one or more of the transmitted frames from said decompressed data generated by said decoder and said decompressed data generated by said decompressor.
2. The apparatus of claim 1 wherein said compressor includes discrete cosine transform circuitry for performing a discrete cosine transform on said decompressed data generated by said decoder to generate transformed data.
3. The apparatus of claim 2 wherein said compressor further includes quantization circuitry coupled to said discrete cosine transform circuitry for quantizing said transformed data to generate quantized transformed data.
4. The apparatus of claim 3 wherein said compressor further includes entropy encoding circuitry coupled to said quantization circuitry for variable length encoding said quantized transformed data.
5. The apparatus of claim 1 wherein said decompressor includes entropy decoding circuitry coupled to said memory for decoding selected variable length data stored in said memory to generate corresponding decompressed data.
6. The apparatus of claim 5 wherein said decompressor further includes inverse quantization circuitry coupled to said entropy decoding circuitry for inverse quantizing said decompressed data generated by said entropy decoding circuitry to generate inverse quantized data.
7. The apparatus of claim 6 wherein said decompressor further includes inverse discrete cosine transform circuitry coupled to said inverse quantization circuitry for performing an inverse discrete cosine transform on said inverse quantized data to generate decompressed data for reconstruction of the transmitted frames.
8. The apparatus of claim 1 further comprising a display coupled to said decoder for displaying the reconstructed transmitted frames.
9. Apparatus for decoding a stream of compressed video data, wherein the stream includes a plurality of variable length encoded data representing image areas of transmitted frames, comprising: a decoder for decoding a predetermined number of blocks of variable length encoded data to generate a corresponding number of blocks of decompressed data for reconstruction of the transmitted frames; memory coupled to said decoder; a compressor coupled to said decoder and said memory for variable length encoding in parallel the blocks of decompressed data generated by said decoder for direct storage in said memory as variable length encoded data; a rate control circuit coupled to said compressor for controlling a rate at which said compressor stores said variable length encoded data in said memory, wherein said rate control circuit is operable to allocate a fixed number of bits for the number of blocks of variable length encoded data, allocate a variable number of bits for each block of variable length encoded data, monitor the number of bits generated by the compressor during the encoding of the blocks of decompressed data, and terminate the encoding of the blocks of decompressed data so that the allocated fixed number of bits for the number of blocks of variable length encoded data is not exceeded; and a decompressor coupled to said memory and said decoder for decoding selected variable length encoded data stored in said memory to generate corresponding decompressed data, whereby said decoder is operable to reconstruct one or more of the transmitted frames from said decompressed data generated by said decoder and said decompressed data generated by said decompressor.
10. The apparatus of claim 9 further including a display for displaying the reconstructed transmitted frames.
11. A method for decoding a stream of compressed video data, wherein the stream includes a plurality of variable length encoded data representing image areas of transmitted frames, comprising: decoding a block of variable length encoded data to generate a corresponding block of decompressed data for reconstruction of the transmitted frames; compressing the block of decompressed data by variable length encoding the block of decompressed data to generate a block of variable length encoded data; allocating a fixed number of bits for the block of variable length encoded data; monitoring the number of bits generated during the compressing step; terminating the compressing step so that the allocated fixed number of bits for the block of variable length encoded data is not exceeded; directly storing the variable length encoded data in memory; decompressing selected variable length encoded data stored in memory to generate corresponding decompressed data; and selectively combining the decompressed data generated during the decoding step and the decompressed data generated during the decompressing step to reconstruct one or more of the transmitted frames.
12. The method of claim 11 wherein the compressing step includes the step of performing a discrete cosine transform on the decompressed data generated during the decoding step to generate transformed data.
13. The method of claim 12 wherein the compressing step further includes the step of quantizing the transformed data to generate quantized transformed data.
14. The method of claim 13 wherein the compressing step further includes the step of entropy encoding the quantized transformed data.
15. The method of claim 11 further including the step of displaying the reconstructed transmitted frames.
16. A method for decoding a stream of compressed video data, wherein the stream includes a plurality of variable length encoded data representing image areas of transmitted frames, comprising: decoding a predetermined number of blocks of variable length encoded data to generate a corresponding number of blocks of decompressed data for reconstruction of the transmitted frames; compressing the blocks of decompressed data by variable length encoding the blocks of decompressed data in parallel to generate a corresponding number of blocks of variable length encoded data; allocating a fixed number of bits for the number of blocks of variable length encoded data; allocating a variable number of bits for each block of variable length encoded data; monitoring the number of bits generated during the compressing step; terminating the compressing step so that the allocated fixed number of bits for the number of blocks of variable length encoded data is not exceeded; directly storing the variable length encoded data in memory; decompressing selected variable length encoded data stored in memory to generate corresponding decompressed data; and selectively combining the decompressed data generated during the decoding step and the decompressed data generated during the decompressing step to reconstruct one or more of the transmitted frames.
17. The method of claim 16 wherein the compressing step includes the step of performing a discrete cosine transform on the decompressed data generated during the decoding step to generate transformed data.
18. The method of claim 17 wherein the compressing step further includes the step of quantizing the transformed data to generate quantized transformed data.
19. The method of claim 18 wherein the compressing step further includes the step of entropy encoding the quantized transformed data.
20. The method of claim 16 further including the step of displaying the reconstructed transmitted frames.
21. A method for decoding a stream of compressed video data, wherein the stream includes a plurality of variable length encoded data representing image areas of transmitted frames, comprising: decoding a predetermined number of blocks of variable length encoded data to generate a corresponding number of blocks of decompressed data for reconstruction of the transmitted frames; compressing the blocks of decompressed data by variable length encoding the blocks of decompressed data to generate a corresponding number of blocks of variable length encoded data; allocating a fixed number of bits for the number of blocks of variable length encoded data; allocating a variable number of bits for each block of variable length encoded data; monitoring the number of bits generated during the compressing step; altering the compressing step so that the allocated fixed number of bits for the number of blocks of variable length encoded data is not exceeded; directly storing the variable length encoded data in memory; decompressing selected variable length encoded data stored in memory to generate corresponding decompressed data; and selectively combining the decompressed data generated during the decoding step and the decompressed data generated during the decompressing step to reconstruct one or more of the transmitted frames.
22. The method of claim 21 wherein the compressing step includes the step of performing a discrete cosine transform on the decompressed data generated during the decoding step to generate transformed data.
23. The method of claim 22 wherein the compressing step further includes the step of quantizing the transformed data to generate quantized transformed data.
24. The method of claim 23 wherein the compressing step further includes the step of entropy encoding the quantized transformed data.
25. The method of claim 21 further including the step of displaying the reconstructed transmitted frames.
26. The apparatus of claim 9 wherein said compressor includes discrete cosine transform circuitry for performing a discrete cosine transform on said decompressed data generated by said decoder to generate transformed data.
27. The apparatus of claim 26 wherein said compressor further includes quantization circuitry coupled to said discrete cosine transform circuitry for quantizing said transformed data to generate quantized transformed data.
28. The apparatus of claim 27 wherein said compressor further includes entropy encoding circuitry coupled to said quantization circuitry for variable length encoding said quantized transformed data.
29. The apparatus of claim 9 wherein said decompressor includes entropy decoding circuitry coupled to said memory for decoding selected variable length data stored in said memory to generate corresponding decompressed data.
30. The apparatus of claim 29 wherein said decompressor further includes inverse quantization circuitry coupled to said entropy decoding circuitry for inverse quantizing said decompressed data generated by said entropy decoding circuitry to generate inverse quantized data.
31. The apparatus of claim 30 wherein said decompressor further includes inverse discrete cosine transform circuitry coupled to said inverse quantization circuitry for performing an inverse discrete cosine transform on said inverse quantized data to generate decompressed data for reconstruction of the transmitted frames.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
October 26, 1998
May 8, 2001
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